package com.zmzncs.shop.common.util;

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Util {

    public static void main(String[] args) {
        System.out.println(generatePassword("admin"));

        System.out.println(md5("a4ed2cfe01100ca92ce4ddc0634c72ba" + "630242567"));
//        System.out.println(generatePassword("a4ed2cfe01100ca92ce4ddc0634c72ba" + "630242567"));
    }

    /**
     * md5加密
     */
    public static String md5(String str){
        try {
            // 生成一个MD5加密计算摘要
            MessageDigest messageDigest = MessageDigest.getInstance("MD5");
            // 计算md5函数
            messageDigest.update(str.getBytes());
            // digest()最后确定返回md5 hash值，返回值为8为字符串。因为md5 hash值是16位的hex值，实际上就是8位的字符
            // BigInteger函数则将8位的字符串转换成16位hex值，用字符串来表示；得到字符串形式的hash值
            return new BigInteger(1, messageDigest.digest()).toString(16);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 生成密码
     */
    public static String generatePassword(String passwork){
        try {
            // 生成一个MD5加密计算摘要
            MessageDigest messageDigest = MessageDigest.getInstance("MD5");
            // 计算md5函数
            messageDigest.update(("中萌智能城市" + passwork).getBytes());
            // digest()最后确定返回md5 hash值，返回值为8为字符串。因为md5 hash值是16位的hex值，实际上就是8位的字符
            // BigInteger函数则将8位的字符串转换成16位hex值，用字符串来表示；得到字符串形式的hash值
            return new BigInteger(1, messageDigest.digest()).toString(16);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    private static String byteArrayToHexString(byte b[]) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++)
            resultSb.append(byteToHexString(b[i]));
        return resultSb.toString();
    }

    public static String MD5Encode(String origin, String charsetname) {
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (charsetname == null || "".equals(charsetname))
                resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
            else
                resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));
        } catch (Exception exception) {
        }
        return resultString;
    }

    //32位大写toUpperCase()
    public static String md5ToUpperCase(String string) {
        String re_md5 = new String();
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(string.getBytes());
            byte b[] = md.digest();
            int i;
            StringBuffer buf = new StringBuffer("");
            for (int offset = 0; offset < b.length; offset++) {
                i = b[offset];
                if (i < 0)
                    i += 256;
                if (i < 16)
                    buf.append("0");
                buf.append(Integer.toHexString(i));
            }
            re_md5 = buf.toString().toUpperCase();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return re_md5;
    }

    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n += 256;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    public static String convertMD5(String inStr) {
        char[] a = inStr.toCharArray();
        for (int i = 0; i < a.length; i++) {
            a[i] = (char) (a[i] ^ 't');
        }
        String s = new String(a);
        return s;
    }

    private static final String hexDigits[] = {"0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};

}